The Meaning of Rest Assured: What It Is and How To Use It

Do you know what the phrase rest assured means? This article will provide you with all of the information you need on the phrase rest assured, including its meaning, usage, synonyms, origin, useful sentence examples, and more!

Your writing, at its best

Compose bold, clear, mistake-free, writing with Grammarly's AI-powered writing assistant

What does the phrase rest assured mean?

According to Dictionary, Cambridge English Dictionary, and other English language dictionary apps, the phrase rest assured means “you can be sure” or to be certain or confident that something is going to happen. The expression rest assured uses the word assured to mean “certain” or “confident.” This phrase also uses the word rest to mean remain. Therefore, the meaning of the expression is “remain certain,” or “believe.” This phrase can be used in many different ways. It is usually used to tell someone not to worry, and that they can be confident about whatever it is that they are waiting to happen.  For example, someone can tell someone who is waiting on medical results, “Rest assured, whatever the outcome, I will be there for you.” They could also use it to tell someone who just got broken up with, “Rest assured, this is a good thing. You will find someone new and have an even better relationship.” In this phrase, the word rest is a verb and the word assured is an adverb, since it is describing how the person should rest. 

What is the etymology of the phrase rest assured?

According to Etymonline, people have been using the word rest to mean to be left or to remain since the mid-15th century. This word comes from the Old French rester, meaning to remain, which takes its roots in the Latin restare, meaning to stand back or be left. This Latin word comes from the prefix re- meaning back, and the root stare, which means to stand. The phrase rest assured became common between the 16th and 17th centuries. In the phrase rest assured, assured is used to mean “certain” or “confident,” which is a usage dating back to the early 1500s. 

What are synonyms for the phrase rest assured?

There are many different ways that someone can say the phrase rest assured. Someone might choose to use a synonym, which is a word or phrase that means the same thing as another word or phrase, in order to grow their vocabulary or to avoid repeating themselves. According to Thesaurus, all of the below words are synonyms for the phrase rest assured.

  • conclude
  • accept
  • have
  • accredit
  • fall for
  • have no doubt
  • affirm
  • conceive
  • presuppose
  • attach weight to
  • be credulous
  • count on
  • hold
  • take it
  • admit
  • take as gospel
  • swallow
  • give credence to
  • buy
  • trust
  • posit
  • lap up
  • place confidence in
  • consider
  • presume true
  • regard
  • swear by
  • take at one’s word
  • reckon on
  • deem
  • take for granted
  • keep the faith
  • credit
  • think
  • suppose
  • be certain of
  • believe
  • have faith in
  • be convinced of
  • understand
  • postulate
  • be of the opinion

What if someone wanted to tell someone the opposite of rest assured? In this case, that person should use an antonym, which is a word or phrase that means the opposite of another word or phrase. This list of antonyms is also provided by Thesaurus.

  • be undetermined
  • hesitate
  • insinuate
  • not buy
  • discredit
  • call in question
  • doubt
  • be in a quandary
  • scruple
  • misdoubt
  • smell a rat
  • fluctuate
  • challenge
  • shilly-shally
  • have qualms
  • skepticize
  • dispute
  • fear
  • mistrust
  • waver
  • be dubious
  • imagine
  • be curious
  • disbelieve
  • distrust
  • impugn
  • be apprehensive of
  • wonder at
  • be puzzled
  • vacillate
  • be uncertain
  • suspect
  • demur
  • harbor suspicion
  • read differently
  • misgive
  • take dim view of
  • surmise
  • give no credence
  • query

How can the phrase rest assured be used in a sentence?

The phrase rest assured can be used in many different situations. The phrase is considered polite, so one does not need to worry about it being too casual or informal to use in more professional situations. In this first example, Margarita is frustrated when talking with her English teacher Jane.

Margarita: It’s no use. I’ll never fully learn English. It’s too hard. I hate being in E S L classes.

Jane: Margarita, don’t be so hard on yourself. English is one of the hardest languages in the world to learn. And look at you, you can communicate just fine. Rest assured, you’re in good hands. Next thing you know, you’ll be top of your class.

Margarita: Are you sure?

Jane: I’m positive. Now let’s get back to some English grammar lessons.

Here, Jane uses the phrase rest assured to tell Margarita to be confident in her abilities and that her knowledge of the English language will progress. In this next example, Natalya and Kevin are buying new furniture for their outdoor patio area. A salesman comes up to them.

Salesman: What are we looking at today?

Natalya: We’re looking at some new patio furniture, and maybe a hammock.

Salesman: Very nice! This set over here is one of our most popular sellers.

Kevin: Are you sure it’s good quality? It seems awfully discounted.

Salesman: Rest assured, these pieces are great. I have them at my own house. They come with covers for when it rains, and they’re very very comfortable. Plus, they have a 30-day money back guarantee, so if they’re not up to your standards, you can get a full refund, no questions asked.

Natalya: These are comfortable, Kevin.

Kevin: Alright, I’m sold!

Overall, the phrase rest assured means to be sure or to be confident that something is going to happen. This phrase uses the word rest to mean remain, and the word assured to mean certain or confident. This phrase can be used to tell people not to worry or to remain confident that something will happen.